Refrigeration device

ABSTRACT

Disposed is a contaminant recovery receptacle ( 40 ) which is connected, through an inflow pipe ( 42 ) and an outflow pipe ( 43 ), to the suction side of a compressor ( 21 ). The inflow pipe ( 42 ) has an exit end which opens towards the inner bottom of the recovery receptacle ( 40 ). The outflow pipe ( 43 ) has an entrance end which is situated above the exit end of the inflow pipe ( 42 ) in the recovery receptacle ( 40 ). Firstly, a preliminary operation is carried out which causes refrigerant to circulate in a refrigerant circuit ( 10 ) for a predetermined length of time so that gas-liquid two-phase refrigerant flows into the recovery receptacle ( 40 ). Thereafter, a recovery operation is carried out, which causes refrigerant to circulate in the refrigerant circuit ( 10 ) so that gas refrigerant flows into the recovery receptacle ( 40 ). As a result, contaminants are recovered in the recovery receptacle ( 40 ).

TECHNICAL FIELD

This invention generally relates to refrigeration apparatuses, and itrelates more specifically to a refrigeration apparatus having arefrigerant circuit which enables a refrigerant-pipe cleaning operation.

BACKGROUND ART

Conventionally, refrigeration apparatuses, such as an air conditioningapparatus with a refrigerant circuit in which refrigerant circulates toperform a vapor compression refrigeration cycle, use refrigerants of theCFC (chlorofluorocarbon) family or refrigerants of the HCFC(hydrochlorofluorocarbon) family. However, the use of these refrigerantsof the CFC/HCFC families gives rise to environmental problems such asozone layer destruction. It is desired that these existing refrigerationapparatuses are renewed to new ones that employ refrigerants of the HFC(hydrofluorocarbon) family or refrigerants of the HC (hydrocarbon)family.

Refrigerant pipes for establishing connections between a heat sourceunit and utilization units are practically buried into inner areas of abuilding, therefore impeding replacement of such buried refrigerantpipes with new ones. For the purpose of shortening work periods andcutting costs down, the introduction of new refrigeration apparatuses ismade while utilizing existing refrigerant pipes as they are.

Apart from the above, contaminants (e.g., refrigeration oil used inconventional refrigeration apparatuses employing CFC- or HCFC-familyrefrigerants with a chlorine content) remain as residual materials inexisting refrigerant pipes. Conventionally, naphthenic mineral oil isoften used as a refrigeration oil. If naphthenic mineral oil remainingas a residual material in an existing pipe degrades, this may give riseto the problem of corrosion of for example an expansion valve by thepresence of chlorine ions and acids in the degraded mineral oil.

Accordingly when introducing a new refrigeration apparatus, it isnecessary to clean existing refrigerant pipes to remove residualcontaminants in the existing refrigerant pipes, prior to performing atest run on the new refrigeration apparatus.

To this end, there is proposed a refrigeration apparatus equipped with arefrigerant circuit which enables execution of an operation of cleaningexisting refrigerant pipes (see, for example, Patent Document 1,Japanese Patent Laid-open Publication No. JP 2001-41613). Therefrigeration apparatus of Patent Document 1, Japanese Patent Laid-openPublication No. JP 2001-41613 is provided with a refrigerant circuitformed by connection of a heat source machine mainly made up of acompressor and a heat source side heat exchanger with an indoor unithaving a utilization side heat exchanger through existing connectionpipes. And, an oil recovery unit for separating contaminants (such asresidual refrigeration oil) from the refrigerant and recovering them isprovided in a suction side pipe of the compressor.

The refrigeration apparatus of Patent Document 1 is configured, suchthat after the fill-up of the refrigerant circuit with a refrigerant ofthe HFC family, the compressor is activated and the refrigerationapparatus operates in cooling mode or in heating mode; existingconnection pipes are cleaned by the refrigerant circulating in therefrigerant circuit; and contaminants (such as residual refrigerationoil) are recovered in the oil recovery unit.

Problems that Invention Intends to Solve

The oil recovery unit of the above-described refrigeration apparatus isequipped with a filter unit made up of a microporous member forseparating contaminants (residual refrigeration oil) from therefrigerant entered into the oil recovery unit and an adsorptivematerial for recovering the separated contaminants.

It, however, suffices if contaminants in refrigerant pipes are recoveredto such an extent that after renewal, there occurs no serious troubleduring the normal operation.

The problem with the oil recovery unit is that its structure becomescomplicated as a result of obtaining higher-than-necessary levels ofcontaminant separation/recovery performance.

With the above problems in mind, the present invention was made.Accordingly, an object of the present invention is to provide arefrigeration apparatus equipped with a structure-simplified oilrecovery unit capable of moderate separation/recovery of contaminantswithout interfere with the normal operation.

DISCLOSURE OF INVENTION

More specifically, a first invention of the present application isdirected to a refrigeration apparatus, comprising (a) a refrigerantcircuit (10) for execution of a vapor compression refrigeration cycleincluding a compressor (21), a heat source side heat exchanger (24), anda utilization side heat exchanger (33) which are connected by arefrigerant pipe and (b) a contaminant recovery receptacle (40) which isconnected to the suction side of the compressor (21) by an inflow pipe(42) and an outflow pipe (43), for recovering contaminants in therecovery receptacle (40) by causing refrigerant to circulate in therefrigerant circuit (10) so that gaseous refrigerant flows into therecovery receptacle (40). In the refrigeration apparatus of the firstinvention, the inflow pipe (42) has an exit end which opens downwardlyor obliquely downwardly in the recovery receptacle (40) while, on theother hand, the outflow pipe (43) has an entrance end which is situatedabove the exit end of the inflow pipe (42) in the recovery receptacle(40).

In the first invention, by the circulating of refrigerant in therefrigerant circuit (10), contaminants in the refrigerant pipe areforced to flow, together with gas refrigerant, into the recoveryreceptacle (40) by way of the inflow pipe (42) and, as a result, therefrigerant pipe is cleaned.

As described above, the exit end of the inflow pipe (42) opens eitherdownwardly or obliquely downwardly in the recovery receptacle (40) and,on the other hand, the entrance end of the outflow pipe (43) is situatedabove the exit end of the inflow pipe (42) in the recovery receptacle(40). As a result of such arrangement, the gas refrigerant entered intothe recovery receptacle (40) by way of the inflow pipe (42) will notflow directly into the outflow pipe (43), but it is introduced towardsthe inner bottom of the recovery receptacle (40) without fail. Since theflow velocity of the gas refrigerant introduced towards the inner bottomof the recovery receptacle (40) is slower than the circulation flowvelocity in the refrigerant circuit (10), contaminants are separated andremoved from the gas refrigerant, and only the gas refrigerant is flowedout into the refrigerant circuit (10) by way of the outflow pipe (43).

In addition, a second invention according to the first invention isdisclosed which is characterized in that a baffle plate (44) againstcontaminants is so disposed as to be situated face to face with theentrance end of the outflow pipe (43) at a predetermined distance aparttherefrom in the recovery receptacle (40).

In the second invention, it is ensured that the inflow of contaminants(separated from the gas refrigerant introduced to the inner bottom ofthe recovery receptacle (40)) into the outflow pipe (43) due torebounding is prevented.

In addition, a third invention according to the first invention isdisclosed which is characterized in that it comprises a switching means(50) for switching the circulation of refrigerant in the refrigerantcircuit (10) so that the refrigerant is either circulated to flowthrough the recovery receptacle (40), or circulated to bypass therecovery receptacle (40), wherein the switching means (50) is made up ofopening/closing valves (51, 52) disposed, respectively, in the inflowand outflow pipes (42, 43) of the recovery receptacle (40), and anopening/closing valve (53) disposed between a connection part of theinflow pipe (42) and a connection part of the outflow pipe (43) of therecovery receptacle (40) in a refrigerant pipe on the suction side ofthe compressor (21).

In the third invention, it is arranged that during the pipe cleaningoperation, the opening/closing valves (51, 52) each change state to theopen state while, on the other hand, the opening/closing valve (53)changes state to the closed state, whereby the refrigerant is circulatedin the refrigerant circuit (10) so that it flows through the recoveryreceptacle (40). And, during the normal operation after the pipecleaning operation has been completed, the opening/closing valves (51,52) each change state to the closed state while, on the other hand, theopening/closing valve (53) changes state to the open state, whereby therefrigerant is circulated in the refrigerant circuit (10) so that itbypasses the recovery receptacle (40). As a result, the refrigerant iscirculated, such that it will never flow through the recovery receptacle(40) during the normal operation, and the operation of the refrigerationapparatus is carried out safely.

In addition, a fourth invention according to the first invention isdisclosed which is characterized in that an auxiliary liquid for therecovery of contaminants is pre-stored in the recovery receptacle (40),and that the exit end of the inflow pipe (42) of the recovery receptacle(40) is situated at a predetermined distance apart from the storagesurface of the contaminant-recovery auxiliary liquid.

In the fourth invention, contaminants contained in gas refrigerantintroduced to the inner bottom of the recovery receptacle (40) areattracted by attraction force (surface tension) in the storage surfaceof the contaminant recovery auxiliary liquid. This assures separation ofcontaminants from gas refrigerant introduced to the inner bottom of therecovery receptacle (40).

Since the exit end of the inflow pipe (42) is positioned at apredetermined distance away from the storage surface of thecontaminant-recovery auxiliary liquid, this prevents gas refrigerantfrom being discharged, through the inflow pipe (42), into thecontaminant-recovery auxiliary liquid. As a result, gas refrigerantentered into the recovery receptacle (40) is flowed out into therefrigerant circuit (10) by way of the outflow pipe (43), and theincrease in gas refrigerant's pressure loss in the recovery receptacle(40) is prevented.

In addition, a fifth invention according to the first invention isdisclosed which is characterized in that it comprises a preliminaryoperation means (60) for causing refrigerant to circulate in therefrigerant circuit (10) for a predetermined length of time so that atwo-phase refrigerant mixture of liquid refrigerant and gas refrigerantflows into the recovery receptacle (40), and a recovery operation means(70) for causing refrigerant to circulate in the refrigerant circuit(10) so that upon completion of the operation of the preliminaryoperation means (60), gaseous refrigerant flows into the recoveryreceptacle (40).

In the fifth invention, liquid refrigerant and contaminants areseparated from a so-called two-phase refrigerant mixture of liquidrefrigerant and gas refrigerant flowed into the recovery receptacle (40)by the preliminary operation means (60), and the separated liquidrefrigerant and contaminants are stored in the recovery receptacle (40).Stated another way, this is the same state as the state that thecontaminant-recovery auxiliary liquid is stored in the recoveryreceptacle (40) in the fourth invention.

And, upon completion of the operation of the preliminary operation means(60), contaminants present in the gas refrigerant introduced to theinner bottom of the recovery receptacle (40) by the recovery operationmeans (70) are attracted to the storage surface of the stored liquidrefrigerant. Accordingly, it is ensured that contaminants are separatedfrom gas refrigerant introduced to the inner bottom of the recoveryreceptacle (40).

In addition, a sixth invention according to the fifth invention isdisclosed which is characterized in that the preliminary operation means(60) increases the degree of opening of an expansion valve (32) disposedbetween the heat source side heat exchanger (24) and the utilizationside heat exchanger (33).

In the sixth invention, the liquid refrigerant entered into theexpansion valve (32) is less restricted than in the normal operation,and the amount of refrigerant in the utilization side heat exchanger(33) increases. As a result, a part of refrigerant entered into theutilization side heat exchanger (33) is left unvaporized and remainsstill in the form of liquid refrigerant. This ensures that a gas-liquidtwo-phase refrigerant mixture of liquid refrigerant and gas refrigerantflows into the recovery receptacle (40), thereby assuring the storage ofliquid refrigerant in the recovery receptacle (40).

In addition, a seventh invention according to the fifth invention isdisclosed which is characterized in that the preliminary operation means(60) stops a utilization side fan of the utilization side heat exchanger(33).

In the seventh invention, a supply of air as a heat transfer medium isnot provided to the utilization side heat exchanger (33) and, as aresult, the evaporation amount of refrigerant in the utilization sideheat exchanger (33) is reduced. This assures inflow of a gas-liquidtwo-phase refrigerant mixture of liquid refrigerant and gas refrigerantinto the recovery receptacle (40), as in the sixth invention.Consequently, it is ensured that liquid refrigerant is stored in therecovery receptacle (40).

Finally, an eighth invention according to the fifth invention isdisclosed which is characterized in that the preliminary operation means(60) lowers the frequency of the compressor (21) to below apredetermined value.

In the eighth invention, the amount of refrigerant drawn into thecompressor (21) is reduced and, as a result, the amount of refrigerantin the utilization side heat exchanger (33) increases. In other words,this is the state in which the degree of opening of the expansion valve(32) apparently increases, thereby assuring inflow of a gas-liquidtwo-phase refrigerant mixture of gas refrigerant and liquid refrigerantinto the recovery receptacle (40).

Effects of Invention

As described above, in accordance with the present invention, therecovery receptacle (40) is provided in the refrigerant circuit (10),and refrigerant is circulated through the refrigerant circuit (10) sothat gas refrigerant flows into the recovery receptacle (40), wherebythe refrigerant pipe is cleaned.

Especially, in accordance with the first invention, it is arranged thatthe exit end of the inflow pipe (42) opens downwardly or obliquelydownwardly in the recovery receptacle (40) while, on the other hand, theentrance end of the outflow pipe (43) is situated above the exit end ofthe inflow pipe (42). As a result of such arrangement, gas refrigerantdischarged from the inflow pipe (42) is not entered directly into theoutflow pipe (43), but it is discharged towards the inner bottom of therecovery receptacle (40), and contaminants are separated from the gasrefrigerant. Then, only the gas refrigerant is flowed out through theoutflow pipe (43). The recovery receptacle (40) has a function ofseparating contaminants from gas refrigerant and colleting the separatedcontaminants, and is simple in structure.

In addition, in accordance with the second invention, it is arrangedthat the baffle plate (44) is disposed face to face with the entranceend of the outflow pipe (43) at a predetermined distance apart therefromin the recovery receptacle (40). Such arrangement prevents outflow ofcontaminants, introduced into the recovery receptacle (40) together withgas refrigerant and then separated from the gas refrigerant, through theoutflow pipe (43) due to rebounding. This therefore ensures thatcontaminants are recovered in the recovery receptacle (40) without fail.

In addition, in accordance with the third invention, it is arranged thatthe switching means (50) is made up of the opening/closing valves (51,52) disposed respectively in the inflow and outflow pipes (42, 43) ofthe recovery receptacle (40), and the opening/closing valve (53)disposed between the connection part of the inflow pipe (42) and theconnection part of the outflow pipe (43) of the recovery receptacle (40)in the refrigerant pipe on the suction side of the compressor (21). As aresult of such arrangement, during the normal operation after completionof the pipe cleaning, refrigerant can be circulated in the refrigerantcircuit (10) without flowing through the recovery receptacle (40).Consequently, contaminants are confined in the recovery receptacle (40),thereby making it possible to safely carry out normal operations.

In addition, in accordance with the fourth invention, it is arrangedthat contaminant recovery auxiliary liquid is pre-stored in the recoveryreceptacle (40). In accordance with the fifth invention, refrigerant iscirculated in the refrigerant circuit (10) so that a two-phaserefrigerant mixture of liquid refrigerant and gas refrigerant flows intothe recovery receptacle (40). As the result of such arrangements,contaminants contained in gas refrigerant entered into the recoveryreceptacle (40) are attracted to the surface of the contaminant recoveryauxiliary liquid and adhered thereto. It is ensured that thecontaminants are separated from the gas refrigerant and then collectedin the recovery receptacle (40).

In addition, in accordance with the sixth invention, it is arranged thatthe degree of opening of the expansion valves (25 (32)) is made greaterthan normal by the preliminary operation means (60). In accordance withthe seventh invention, it is arranged that the utilization side fan isstopped by the preliminary operation means (60). In accordance with theeighth invention, it is arranged that the frequency of the compressor(21) is reduced to less than a predetermined value. As the result ofsuch arrangements, either the amount of refrigerant in the utilizationside heat exchanger (33) is increased or the evaporation amount ofrefrigerant in the utilization side heat exchanger (33) is decreased. Itis ensured that refrigerant flowing past the utilization side heatexchanger (33) is circulated in a gas-liquid two-phase state. Thistherefore ensures storage of liquid refrigerant in the recoveryreceptacle (40).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a refrigerant circuit diagram of an air conditioning apparatusaccording to a first embodiment of the present invention;

FIG. 2 shows in cross section a schematic structure of a recoveryreceptacle according to the first embodiment;

FIG. 3 shows in cross section a schematic structure of a recoveryreceptacle according to a second embodiment of the present invention;

FIG. 4 shows in cross section a schematic structure of a recoveryreceptacle according to a third embodiment of the present invention;

FIG. 5 shows in cross section a schematic structure of a recoveryreceptacle according to a fourth embodiment of the present invention;

FIG. 6 shows in cross section a schematic structure of a recoveryreceptacle according to a fifth embodiment of the present invention;

FIG. 7 shows in cross section a schematic structure of a recoveryreceptacle according to a sixth embodiment of the present invention;

FIG. 8 shows in cross section a schematic structure of a recoveryreceptacle according to a seventh embodiment of the present invention;and

FIG. 9 shows in cross section a schematic structure of a recoveryreceptacle according to an eighth embodiment of the present invention.

BEST MODE FOR CARRYING OUT INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawing figures.

Embodiment 1 of Invention

Referring to FIG. 1, there is shown a refrigeration apparatus (1) of afirst embodiment of the present invention. The refrigeration apparatus(1) is provided with a refrigerant circuit (10) through whichrefrigerant is circulated for execution of a vapor compressionrefrigeration cycle.

The refrigerant circuit (10) includes an outdoor unit (20) which is aheat source unit and a plurality of indoor units (30) (three indoorunits (30) in the first embodiment) which are utilization side units.The outdoor unit (20) is connected to the indoor units (30) by existingpipes, namely a liquid pipe (A) and a gas pipe (B). And, the outdoorunit (20) and the indoor units (30) are renewed units using arefrigerant of the HFC family.

The three indoor units (30) are connected in parallel to respectiverefrigerant pipes branched off from the liquid pipe (A) and torespective refrigerant pipes branched off from the gas pipe (B). Eachindoor unit (30) is formed by piping connection of an indoor expansionvalve (32) which is an expansion valve and an indoor heat exchanger (33)which is a utilization side heat exchanger. In addition, one of theindoor heat exchangers (33) is provided with an indoor fan (33 a) whichis a utilization side fan.

The outdoor unit (20) is formed by sequential piping connection of acompressor (21), an oil separator (22), a four-way switching valve (23),an outdoor heat exchanger (24) which is a heat source side heatexchanger, and an outdoor expansion valve (25). In addition, the outdoorheat exchanger (24) is provided with an outdoor fan (24 a).

A first closing valve (26) which is a flowpath opening/closing means isprovided at an end of a pipe on the side of the outdoor expansion valve(25) in the outdoor unit (20), and one end of the liquid pipe (A) isconnected, through the first closing valve (26), to the pipe end. On theother hand, a second closing valve (27) which is a flowpathopening/closing means is provided at an end of a pipe on the side of thefour-way switching valve (23) in the outdoor unit (20), and one end ofthe gas pipe (B) is connected, through the second closing valve (27), tothe pipe end.

The other end of the liquid pipe (A) is connected, through a connectionimplement (31), such as a flare joint, to an end of a pipe on the sideof the indoor expansion valve (32) in each indoor unit (30). On theother hand, the other end of the gas pipe (B) is connected, through aconnection implement (34), such as a flare joint, to an end of a pipe onthe side of the indoor heat exchanger (33) in each indoor unit (30).

The refrigerant circuit (10) is configured, such that it is selectivelyoperated in cooling mode and in heating mode by the switching of thefour-way switching valve (23). In other words, if the four-way switchingvalve (23) changes state to a first state (indicated by solid lines inFIG. 1), this causes refrigerant to circulate in the refrigerant circuit(10) in cooling mode of operation in which refrigerant condensationtakes place in the outdoor heat exchanger (24). On the other hand, ifthe four-way switching valve (23) changes state to a second state(indicated by dashed lines in FIG. 1), this causes refrigerant tocirculate in the refrigerant circuit (10) in heating mode of operationin which refrigerant evaporation takes place in the outdoor heatexchanger (24).

For example, in the heating mode of operation, separation/removal of oilfrom refrigerant compressed in the compressor (21) is carried out by anoil separator (22). The refrigerant is condensed in the outdoor heatexchanger (24). Thereafter, the refrigerant passes through the outdoorexpansion valve (25) and expands in each indoor expansion valve (32).Then, the refrigerant is evaporated in each indoor heat exchanger (33),and is brought back again to the compressor (21). Such a refrigerantcirculation is repeatedly carried out.

In the outdoor unit (20), the refrigerant circuit (10) is provided witha recovery receptacle (40) for collecting contaminants. The recoveryreceptacle (40) is connected to a refrigerant pipe between the suctionside of the compressor (21) and the four-way switching valve (23) by aninflow pipe (42) and an outflow pipe (43). An inflow valve (51) and anoutflow valve (52) which are opening/closing valves are disposed in theinflow pipe (42) and in the outflow pipe (43), respectively.

In addition, the refrigerant circuit (10) is provided with a bypass pipe(54) which is a pipe for bypassing the recovery receptacle (40). One endof the bypass pipe (54) is connected between the suction side of thecompressor (21) and the outflow pipe (43) of the recovery receptacle(40) while, on the other hand, the other end of the bypass pipe (54) isconnected between the four-way switching valve (23) and the inflow pipe(42) of the recovery receptacle (40). A bypass valve (53) which is anopening/closing valve is provided in the bypass pipe (54). And, theinflow valve (51), the outflow valve (52), and the bypass valve (53)together constitute a switching means (50).

The refrigerant circuit (10) switches the switching means (50) incooling mode of operation for pipe cleaning. More specifically, theinflow valve (51) and the outflow valve (52) are placed in the openstate while, on the other hand, the bypass valve (53) is placed in theclosed state. This causes refrigerant to circulate through the inflowpipe (42), the recovery receptacle (40), and the outflow pipe (43).Then, the refrigerant circuit (10) switches the switching means (50)during the normal operation after completion of the pipe cleaning. Morespecifically, the inflow valve (51) and the outflow valve (52) areplaced in the closed state while, on the other hand, the bypass valve(53) is placed in the open state. This allows refrigerant to circulatethrough the bypass pipe (54) without passing through the recoveryreceptacle (40).

In addition, one end of an oil return pipe (22 a) is connected to theoil separator (22). The other end of the oil return pipe (22 a) isconnected to a pipe part on the suction side of the compressor (21) andon the downstream side of the recovery receptacle (40). The oil returnpipe (22 a) is configured so that refrigeration oil for the HFC familyrefrigerant separated and removed in the oil separator (22) flowstowards the suction side of the compressor (21) from the oil separator(22).

The refrigerant circuit (10) is controlled by a controller (2). Thecontroller (2) has a preliminary operation means (60) and a recoveryoperation means (70). The preliminary operation means (60) causesrefrigerant to circulate in the refrigerant circuit (10) for apredetermined length of time so that a two-phase refrigerant mixture ofliquid refrigerant and gas refrigerant flows into the recoveryreceptacle (40). On the other hand, the recovery operation means (70)causes refrigerant to circulate in the refrigerant circuit (10) so thatupon completion of the operation of the preliminary operation means(60), gaseous refrigerant flows into the recovery receptacle (40).

As shown in FIG. 2, the recovery receptacle (40) includes ahermetically-sealed casing (41). This casing (41) is shaped like acylinder extending vertically. The inflow pipe (42) is connected to anupper side surface portion of the casing (41) while, on the other hand,the outflow pipe (43) is connected to an upper central portion of thecasing (41).

The inflow pipe (42) has a straight pipe part (42 a) which extendshorizontally. The straight pipe part (42 a) passes completely through asidewall portion of the casing (41), and is introduced into the casing(41). The straight pipe part (42 a) includes, at an inner end thereof, adownwardly curved part (42 b) formed continuously to the inner end. Alower end of the curved part (42 b) serves as an exit end. The exit endis situated centrally in the casing (41).

On the other hand, the outflow pipe (43) has a straight pipe part (43 a)which extends vertically. The straight pipe part (43 a) passescompletely through an upper wall portion of the casing (41), and isintroduced into the casing (41). A lower end of the straight pipe part(43 a) serves as an entrance end. The entrance end is situated at anupper part in the casing (41). That is, the exit end of the inflow pipe(42) opens towards the inner bottom of the recovery receptacle (40)without facing the opening of the entrance end of the outflow pipe (43),in other words the exit end of the inflow pipe (42) is formed, such thatit is oriented in the same direction as the opening of the entrance endof the outflow pipe (43). In addition, the entrance end of the outflowpipe (43) is situated above the exit end of the inflow pipe (42) in therecovery receptacle (40).

A baffle plate (44) shaped like an up-side down dish is provided in therecovery receptacle (40). The baffle plate (44) includes a horizontalmember (44 a) shaped like a flat plate. The horizontal member (44 a) hasan inclined member (44 b) extending, at a slant, downwardly outwardlyfrom each edge. The baffle plate (44) is disposed, such that it facesthe lower end of the outflow pipe (43) at a predetermined distance aparttherefrom. Stated another way, the baffle plate (44) is configured sothat contaminants introduced into the recovery receptacle (40) togetherwith gas refrigerant and separated therefrom are prevented from flowingout through the outflow pipe (43) due to rebounding.

Only the inflow pipe (42), the outflow pipe (43), and the baffle plate(44) are disposed as the componentry within the casing (41) of therecovery receptacle (40) in the first embodiment.

Running Operation

Next, a method of replacing the indoor and outdoor units (20, 30) withnew ones is first described briefly. Then, the running operation of theair conditioning apparatus (1) during pipe cleaning is described.

Method of Replacing Indoor and Outdoor Units

A replacement method, in which for renewal of an existing airconditioning apparatus (1) employing a CFC- or HCFC-family refrigerant,existing liquid and gas pipes (A, B) are utilized intact while existingoutdoor and indoor units (20, 30) are replaced with new outdoor andindoor units (20, 30), will be described below.

In the first place, the old refrigerant of the CFC- or HCFC-family iscollected from the existing air conditioning apparatus (1). With theexisting liquid and gas pipes (A, B) left intact, the existing outdoorand indoor units (20, 30) are disconnected from connection implements(31, 34) such as flare joints and from closing valves (26, 27).Thereafter, new outdoor and indoor units (20, 30) are installed and thenare connected, through the connection implements (31, 34) and theclosing valves (26, 27), to the existing liquid and gas pipes (A, B),thereby to constitute the refrigerant circuit (10).

The newly installed outdoor unit (20) is already filled up withHFC-family refrigerant as a new refrigerant. Therefore, both the firstclosing valve (26) and the second closing valve (27) are placed in theclosed state, and a vacuum is drawn in the indoor unit (30), the liquidpipe (A), and the gas pipe (B), and air, moisture, and so on present inthe units of the refrigerant circuit (10) except the outdoor unit (20)are removed. Then, both the first closing valve (26) and the secondclosing valve (27) are placed in the open state, and the refrigerantcircuit (10) is additionally filled up with HFC-family refrigerant.

Operation during Pipe Cleaning

Next, a pipe cleaning operation, for removal of refrigeration oil forthe old refrigerant remaining especially in the existing liquid and gaspipes (A, B) in the air conditioning apparatus (1), will be describedbelow.

The pipe cleaning operation is an operation which is carried out incooling mode of the air conditioning apparatus (1), in other words, thepipe cleaning operation is carried out when the four-way switching valve(23) is placed in the state indicated by solid lines in FIG. 1. The pipecleaning operation is made up of a first operation (hereinafter called“preliminary operation”) for causing refrigerant to circulate in therefrigerant circuit (10) so that gas-liquid two-phase refrigerant flowsinto the recovery receptacle (40), and a second operation (hereinaftercalled “recovery operation) which is carried out upon completion of thepreliminary operation for causing refrigerant to circulate in therefrigerant circuit (10) so that gas refrigerant flows into the recoveryreceptacle (40).

(A) Preliminary Operation

Firstly, the description will be made on the preliminary operation. Thepreliminary operation is carried out by control from the preliminaryoperation means (60).

With the compressor (21) of the refrigerant circuit (10) stopped, theinflow valve (51) and the outflow valve (52) are placed in the openstate while, on the other hand, the bypass valve (53) is placed in theclosed state. And, the degree of opening of the outdoor expansion valve(25) is set, such that it is fully opened, and the degree of opening ofeach indoor expansion valve (32) is set greater than usual.

When in the above-described state of the refrigerant circuit (10), thecompressor (21) is activated, gas refrigerant compressed in thecompressor (21) is discharged, together with refrigeration oil for theHFC-family refrigerant and they flow into the oil separator (22). In theoil separator (22), the refrigeration oil for the HFC-family refrigerantis separated. The gas refrigerant flows into the outdoor heat exchanger(24) by way of the four-way switching valve (23), exchanges heat withoutside air taken in by the outdoor fan (24 a), and is condensed into aliquid refrigerant.

The condensed liquid refrigerant flows into each indoor expansion valve(32) by way of the outdoor expansion valve (25), the first closing valve(26), and the liquid pipe (A). Since the degree of opening of eachindoor expansion valve (32) is so set as to be greater than normal, theamount of refrigerant flowing into each indoor heat exchanger (33)becomes greater than that in the normal operation. Consequently, most ofthe liquid refrigerant entered into each indoor heat exchanger (33)exchanges heat with indoor air taken in by the indoor fan (33 a), and isevaporated into a gas refrigerant: however, a part of the liquidrefrigerant is left unvaporized, remaining still in a liquid state.Stated another way, refrigerant flowing and passing through each indoorheat exchanger (33) becomes a gas-liquid two-phase refrigerant mixtureof liquid refrigerant and gas refrigerant. The gas-liquid two-phaserefrigerant flows into the recovery receptacle (40) by way of the gaspipe (B), the second closing valve (27), and the four-way switchingvalve (23).

The gas-liquid two-phase refrigerant entered into the recoveryreceptacle (40) flows and passes through the inflow pipe (42), and isdischarged towards the inner bottom of the casing (41). The flowvelocity of the discharged refrigerant is lower than the circulationflow velocity of refrigerant in the refrigerant circuit (10), so thatliquid refrigerant is separated from the gas-liquid two-phaserefrigerant and is stored at the inner bottom of the casing (41). Then,only gas refrigerant is brought back to the refrigerant circuit (10) byway of the outflow pipe (43). The gas refrigerant is again drawn intothe compressor (21).

Then, a preliminary operation accompanied by the above-describedrefrigerant circulation is performed for a predetermined length of time.For example, the predetermined length of time is the time by which alevel sensor (not shown) provided in the recovery receptacle (40) stops,after detecting that the casing (41) is filled with liquid refrigerantto a predetermined level, the compressor (21).

To sum up, by virtue of the preliminary operation, it becomes possibleto fill the recovery receptacle (40) with liquid refrigerant to apredetermined level.

Recovery Operation

Next, the description will be made on the recovery operation. Therecovery operation is carried out upon completion of the preliminaryoperation by control from the recovery operation means (70).

Firstly, with the switching means (50) placed in the same state as inthe preliminary operation, the degree of opening of each indoorexpansion valve (32) is set to the normal opening degree at normaloperation time. When, in the above state of the refrigerant circuit(10), the compressor (21) is activated, refrigerant entered into eachexpansion valve (32) undergoes decompression, exchanges heat with indoorair in the indoor heat exchanger (33), and is evaporated into a gasrefrigerant. The gas refrigerant flows into the recovery receptacle (40)by way of the gas pipe (B), the second closing valve (27), and thefour-way switching valve (23).

By virtue of the above-described refrigerant circulation, contaminants,e.g., refrigeration oil for the old refrigerant lingering in refrigerantpipes (especially, the liquid pipe (A) and the gas pipe (B)) are takenaway therefrom, and flow into the recovery receptacle (40), togetherwith the refrigerant. Thereby, the refrigerant pipes are cleaned.

The gas refrigerant entered into the recovery receptacle (40) flows andpasses through the inflow pipe (42), and is discharged towards the innerbottom of the casing (41). Since the flow velocity of the refrigerantthus discharged falls below the circulation flow velocity of refrigerantin the refrigerant circuit (10), contaminants, such as refrigerationoil, are separated from the gas refrigerant, and are stored in therecovery receptacle (40). Here, the liquid refrigerant is already storedin the recovery receptacle (40) by the above-described preliminaryoperation, so that contaminants entered into the recovery receptacle(40) adhere onto the surface of the liquid refrigerant by suction at thesurface of the liquid refrigerant. This ensures that contaminants areseparated from gas refrigerant entered into the recovery receptacle (40)and are stored in the recovery receptacle (40). And only gas refrigerantflows out into the refrigerant circuit (10) by way of the outflow pipe(43), and is again drawn into the compressor (21). Such a refrigerantcirculation is repeatedly carried out. Thereby, contaminants in therefrigerant pipes are collected in the recovery receptacle (40).

In addition, for example, even if, when gas refrigerant is dischargedtowards the inner bottom of the recovery receptacle (40) from the inflowpipe (42), contaminants separated from the gas refrigerant reboundupwardly to near the entrance end of the outflow pipe (43), thecontaminants will not flow out from the outflow pipe (43) because of thebaffle plate (44) as an obstacle against the contaminants. It is ensuredthat contaminants in the refrigerant pipes are collected in the recoveryreceptacle (40).

Upon completion of the above-described recovery operation, the inflowvalve (51) and the outflow valve (52) are placed in the closed statewhile, on the other hand, the bypass valve (53) is placed in the openstate. Thereafter, the normal operation is enabled, and the refrigerantcirculates in the refrigerant circuit (10) without passing and flowingthrough the recovery receptacle (40).

Effects of Embodiment

As described above, in accordance with the first embodiment, therefrigerant circuit (10) is provided with the recovery receptacle (40),and the switching means (50) is switched for refrigerant to circulate inthe refrigerant circuit (10) so that gas refrigerant flows into therecovery receptacle (40) in cooling mode of operation, thereby making itpossible to clean the refrigerant pipes.

In addition, it is arranged that the exit end of the inflow pipe (42) inthe recovery receptacle (40) opens towards the inner bottom of therecovery receptacle (40) while, on the other hand, the entrance end ofthe outflow pipe (43) is disposed so as to be positioned above the exitend of the inflow pipe (42) in the recovery receptacle (40). Thisarrangement ensures that gas refrigerant which has entered the recoveryreceptacle (40) is discharged towards the inner bottom of the recoveryreceptacle (40) without direct inflow into the outflow pipe (43). And,contaminants are separated from the gas refrigerant by the drop in flowvelocity of the gas refrigerant, thereby ensuring that only gasrefrigerant is flowed out from the outflow pipe (43).

Besides, it is arranged that the baffle plate (44) is disposed to bepositioned face to face with the entrance end of the outflow pipe (43)at a predetermined distance apart therefrom in the recovery receptacle(40). As a result of such arrangement, even if, when the gas refrigerantis discharged towards the inner bottom of the recovery receptacle (40)from the inflow pipe (42), contaminants separated from the gasrefrigerant rebound upwardly to near the entrance end of the outflowpipe (43), the contaminants will not flow out from the outflow pipe(43). This ensures that the contaminants in the refrigerant pipes arerecovered in the recovery receptacle (40).

Additionally, it is arranged that prior to execution of the recoveryoperation, a preliminary operation is carried out for refrigerant tocirculate in the refrigerant circuit (10) so that gas-liquid two-phaserefrigerant flows into the recovery receptacle (40) for the pre-storingof liquid refrigerant in the recovery receptacle (40). As a result ofsuch arrangement, contaminants contained in the gas refrigerant whichhas entered the recovery receptacle (40) is attraction-adhered to theliquid surface of the liquid refrigerant. This assures separation ofcontaminants from gas refrigerant which has entered the recoveryreceptacle (40), and the contaminants are stored in the recoveryreceptacle (40).

Furthermore, it is arranged that the refrigerant circuit (10) isprovided with the switching means (50). As a result of such arrangement,by switching the switching means (50) in the normal operation uponcompletion of the process of pipe cleaning, it becomes possible to causerefrigerant to circulate, without flowing through the recoveryreceptacle (40), in the refrigerant circuit (10) and to confine thecollected contaminants within the recovery receptacle (40). This makesit possible to safely perform the normal operation.

In addition, in the preliminary operation, it is arranged that thedegree of opening of each indoor expansion valve (32) is set greaterthan in the normal operation. Such arrangement ensures that refrigerantwhich has flowed through the indoor heat exchanger (33) flows in theform of a gas-liquid two-phase refrigerant, thereby ensuring that liquidrefrigerant is stored in the recovery receptacle (40).

Embodiment 2 of Invention

Next, a second embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 3, the second embodiment is a modification of the firstembodiment, in other words the inflow pipe (42) of the recoveryreceptacle (40) is modified in location and shape. In addition, unlikethe first embodiment, the provision of the baffle plate (44) in therecovery receptacle (40) is omitted.

More specifically, the inflow pipe (42) is connected to an upper portionof the casing (41). The inflow pipe (42) includes a straight pipe part(42 a) which passes completely through an upper wall portion of thecasing (41) and extends vertically. And, a lower end of the straightpipe part (42 a) is an exit end. The exit end of the inflow pipe (42) issituated near the center of the inside of the casing (41). Morespecifically, the exit end of the inflow pipe (42) opens towards theinner bottom of the recovery receptacle (40), and is formed, such thatit is oriented in the same direction as the entrance end of the outflowpipe (43) without facing the opening of the entrance end of the outflowpipe (43). In addition, the exit end of the inflow pipe (42) is situatedat a lower position than the entrance end of the outflow pipe (43).

The recovery receptacle (40) of the second embodiment provides the sameoperation/working-effect as the recovery receptacle (40) of the firstembodiment. To sum up, in the preliminary operation, gas-liquidtwo-phase refrigerant entered into the recovery receptacle (40) flowsand passes through the inflow pipe (42), and is discharged towards theinner bottom of the casing (41). Liquid refrigerant is separated fromthe discharged refrigerant and is stored at the inner bottom of thecasing (41). Then, only gas refrigerant is flowed out into therefrigerant circuit (10) by way of the outflow pipe (43). In addition,in the recovery operation, gas refrigerant entered into the recoveryreceptacle (40) flows and passes through the inflow pipe (42), and isdischarged towards the inner bottom of the casing (41). Contaminants,such as refrigeration oil, are separated from the discharged refrigerantand are attraction-adhered onto the liquid surface of the liquidrefrigerant stored in the recovery receptacle (40) by the preliminaryoperation. And, only gas refrigerant is flowed out into the refrigerantcircuit (10) by way of the outflow pipe (43). Consequently, contaminantsin the refrigerant pipes are collected in the recovery receptacle (40).

Only the inflow pipe (42) and the outflow pipe (43) are disposed as thecomponentry within the casing (41) of the recovery receptacle (40) inthe second embodiment. The arrangements and theoperation/working-effects of other components including the recoveryreceptacle (40) are the same as in the first embodiment.

Embodiment 3 of Invention

Next, a third embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 4, the third embodiment is a modification of the firstembodiment, in other words the inflow pipe (42) of the recoveryreceptacle (40) is modified in location and shape. In addition, unlikethe first embodiment, the provision of the baffle plate (44) in therecovery receptacle (40) is omitted.

More specifically, the inflow pipe (42) is connected to a bottom sidesurface portion of the casing (41). The inflow pipe (42) includes astraight pipe part (42 a) which passes completely through a side wallportion of the casing (41) and extends horizontally. The straight pipepart (42 a) includes, at an inner end thereof, an upwardly curved part(42 b) formed continuously to the inner end. The curved part (42 b)includes, at an upper end thereof, a straight pipe part (42 c) formedcontinuously to the upper end. In addition, the straight pipe part (42c) includes, at an upper end thereof, a downwardly curved part (42 d)formed continuously to the upper end. And, a lower end of the curvedpart (42 d) is an exit end. The exit end of the curved part (42 d) islocated centrally in the casing (41). More specifically, the exit end ofthe inflow pipe (42) opens towards the inner bottom of the recoveryreceptacle (40), and is formed, such that it is oriented in the samedirection as the entrance end of the outflow pipe (43), without facingthe opening of the entrance end of the outflow pipe (43). In addition,the exit end of the inflow pipe (42) is situated at a lower positionthan the entrance end of the outflow pipe (43).

Only the inflow pipe (42) and the outflow pipe (43) are disposed as thecomponentry within the casing (41) of the recovery receptacle (40) inthe second embodiment. The arrangements and theoperation/working-effects of other components including the recoveryreceptacle (40) are the same as in the first embodiment.

Embodiment 4 of Invention

Next, a fourth embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 5, the fourth embodiment is a modification of thesecond embodiment, in other words the outflow pipe (43) of the recoveryreceptacle (40) is modified in location and shape.

More specifically, the outflow pipe (43) is connected to an upper sidesurface portion of the casing (41). The outflow pipe (43) includes astraight pipe part (43 a) which passes completely through a side wallportion of the casing (41) and extends horizontally. The straight pipepart (43 a) includes, at an inner end thereof, an upwardly curved part(43 b) formed continuously to the inner end. And, an upper end of thecurved part (43 b) is an entrance end. The entrance end of the curvedpart (43 b) is located at a high position in the casing (41). Morespecifically, the entrance end of the outflow pipe (43) is situatedabove the exit end of the inflow pipe (42). The entrance end of theoutflow pipe (43) and the exit end of the inflow pipe (42) open inopposite directions so that their openings are not oriented face to facewith each other.

Such arrangement prevents direct inflow of the refrigerant entered intothe recovery receptacle (40) by way of the inflow pipe (42), into theoutflow pipe (43).

Only the inflow pipe (42) and the outflow pipe (43) are disposed as thecomponentry within the casing (41) of the recovery receptacle (40) inthe fourth embodiment. The arrangements and theoperation/working-effects of other components including the recoveryreceptacle (40) are the same as in the second embodiment.

Embodiment 5of Invention

Next, a fifth embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 6, the fifth embodiment is a modification as a resultof modifying the location and shape of the inflow pipe (42) of therecovery receptacle (40) in the fourth embodiment to the location andshape of the inflow pipe (42) of the recovery receptacle (40) in thefirst embodiment.

More specifically, the exit end of the inflow pipe (42) is situatedbelow the entrance end of the outflow pipe (43). The exit end of theinflow pipe (42) and the entrance end of the outflow pipe (43) open inopposite directions so that their openings are not oriented face to facewith each other.

Only the inflow pipe (42) and the outflow pipe (43) are disposed as thecomponentry within the casing (41) of the recovery receptacle (40) inthe fifth embodiment. The arrangements and the operation/working-effectsof other components including the recovery receptacle (40) are the sameas in the fourth embodiment.

Embodiment 6 of Invention

Next, a sixth embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 7, the sixth embodiment is a modification as a resultof modifying the location and shape of the outflow pipe (43) of therecovery receptacle (40) in the third embodiment to the location andshape of the outflow pipe (43) of the recovery receptacle (40) in thefourth embodiment.

More specifically, the entrance end of the outflow pipe (43) is situatedabove the exit end of the inflow pipe (42). The entrance end of theoutflow pipe (43) and the exit end of the inflow pipe (42) open inopposite directions so that their openings are not oriented face to facewith each other.

Such arrangement prevents direct inflow of the refrigerant entered intothe recovery receptacle (40) by way of the inflow pipe (42), into theoutflow pipe (43).

Only the inflow pipe (42) and the outflow pipe (43) are disposed as thecomponentry within the casing (41) of the recovery receptacle (40) inthe sixth embodiment. The arrangements and the operation/working-effectsof other components including the recovery receptacle (40) are the sameas in the third embodiment.

Embodiment 7 of Invention

Next, a seventh embodiment of the present invention will be described indetail with reference to the drawing figures.

Unlike the first embodiment in which liquid refrigerant is stored in therecovery receptacle (40) by performing a preliminary operation bycontrol from the preliminary operation means (60), in the presentembodiment, however, liquid refrigerant as a contamination-recoveryauxiliary liquid is pre-stored in the recovery receptacle (40).Additionally, the provision of the baffle plate (44) in the recoveryreceptacle (40) is omitted.

To sum up, the preliminary operation is no longer required. Pipecleaning is accomplished by the recovery operation alone. This makes itpossible to aim at reducing the time required for the process of pipecleaning.

Only the inflow pipe (42), the outflow pipe (43), and the contaminationrecovery auxiliary liquid are disposed as the componentry within thecasing (41) of the recovery receptacle (40) in the seventh embodiment.The arrangements and the operation/working-effects of other componentsincluding the recovery receptacle (40) are the same as in the firstembodiment.

Embodiment 8 of Invention

Next, an eighth embodiment of the present invention will be described indetail with reference to the drawing figures.

As shown in FIG. 9, the eighth embodiment is a modification of the firstembodiment, in other words the inflow pipe (42) of the recoveryreceptacle (40) is modified in location and shape.

More specifically, the inflow pipe (42) includes a straight pipe part(42 a) which is connected to an upper side surface portion of the casing(41) and which extends horizontally. The straight pipe part (42 a)passes completely through a side wall portion of the casing (41), and isintroduced into the casing (41). Furthermore, the straight pipe part (42a) includes, at an inner end thereof, an approximately U-curved part (42b) formed continuously to the inner end. The curved part (42 b) curvesat an angle of about 180 degrees from the straight pipe part (42 a) andits lower end which is the exit end of the inflow pipe (42) opensobliquely downwardly. In other words, the exit end of the inflow pipe(42) opens to the side wall of the casing (41).

Other arrangements, such as the arrangement of the refrigerant circuit(10), the arrangement of the outflow pipe (43), and the arrangement ofthe baffle plate (44), are the same as in the first embodiment.

As the result of the above arrangements, gas refrigerant is dischargedobliquely downwardly from the inflow pipe (42) in the recoveryreceptacle (40). At that time, even when contaminants separated from thegas refrigerant rebound upwardly to near the entrance end of the outflowpipe (43), the baffle plate (44) serves as an obstacle against thecontaminants. Therefore, the contaminants will not be flowed out throughthe outflow pipe (43). As the result of this, it is ensured thatcontaminants in the refrigerant pipes are collected in the recoveryreceptacle (40). Other operation/working-effects are the same as in thefirst embodiment.

The curved part (42 b) of the inflow pipe (42) in the present embodimentmay be curved in any other direction. In other words, it may be arrangedthat the curved part (42 b) of the inflow pipe (42) is curved at anangle of about 30 degrees from the straight pipe part (42 a) so that theexit end of the inflow pipe (42) opens obliquely downwardly towards theright-hand side wall of the casing (41).

Other Embodiments of Invention

With respect to each of the foregoing embodiments, the present inventionmay be configured as follows.

In each of the foregoing embodiments, by controlling the degree ofopening of each indoor expansion valve (32) in the preliminaryoperation, refrigerant is circulated in a gas-liquid two-phase stateafter leaving the indoor heat exchanger (33). For example, it may bearranged in the present invention that the indoor fan (33 a) of eachindoor heat exchanger (33) is stopped. In this case, since each indoorheat exchanger (33) is not supplied with indoor air, the evaporationamount of refrigerant in the indoor heat exchanger (33) is reduced,thereby ensuring that refrigerant is entered into a gas-liquid two-phasestate.

Besides, it may be arranged that the frequency of the compressor (21)falls below a predetermined value. In this case, the amount ofrefrigerant drawn into the compressor (21) is reduced and the amount ofrefrigerant in the indoor heat exchanger (33) apparently increases.Consequently, by the same operation as the case where the degree ofopening of the indoor expansion valve (32) is controlled, it becomespossible to cause refrigerant to circulate in a gas-liquid two-phasestate after leaving the indoor heat exchanger (33).

Additionally, it is needless to say that the baffle plate (44) may beprovided within the recovery receptacle (40) in each of the second toseventh embodiments, as in the first embodiment.

Furthermore, in each of the foregoing embodiments, the description hasbeen made in terms of an example in which the number of indoor units(30) is three. Alternatively, one or more indoor units (30) may ofcourse be used.

In addition, the present invention may be applied to other than airconditioning apparatus. For example, the present invention is applicableto various types of refrigeration apparatuses.

Finally, it may be arranged that the exit end of the inflow pipe (42) isoriented so as to open obliquely downwardly towards the side wall of thecasing (41) in each of the second to seventh embodiments, as in theeighth embodiment.

INDUSTRIAL APPLICABILITY

As has been described above, the present invention is suitablyapplicable to refrigeration apparatuses which perform refrigerant pipecleaning operations. The present invention is especially suitable forthe case where refrigeration apparatuses are renewed.

1. A refrigeration apparatus, comprising (a) a refrigerant circuit (10)for execution of a vapor compression refrigeration cycle including acompressor (21), a heat source side heat exchanger (24), and autilization side heat exchanger (33) which are connected by arefrigerant pipe and (b) a contaminant recovery receptacle (40) which isconnected to the suction side of the compressor (21) by an inflow pipe(42) and an outflow pipe (43), for recovering contaminants in therecovery receptacle (40) by causing refrigerant to circulate in therefrigerant circuit (10) so that gaseous refrigerant flows into therecovery receptacle (40), wherein the inflow pipe (42) has an exit endwhich opens downwardly or obliquely downwardly in the recoveryreceptacle (40) while, on the other hand, the outflow pipe (43) has anentrance end which is situated above the exit end of the inflow pipe(42) in the recovery receptacle (40), and wherein a baffle plate (44)against contaminants is so disposed as to be situated face to face withthe entrance end of the outflow pipe (43) at a predetermined distanceapart therefrom in the recovery receptacle (40).
 2. A refrigerationapparatus, comprising (a) a refrigerant circuit (10) for execution of avapor compression refrigeration cycle including a compressor (21) a heatsource side heat exchanger (24) and a utilization side heat exchanger(33) which are connected by a refrigerant pipe and (b) a contaminantrecovery receptacle (40) which is connected to the suction side of thecompressor (21) b an inflow pipe (42) and an outflow pipe (43), forrecovering contaminants in the recovery receptacle (40) by causingrefrigerant to circulate in the refrigerant circuit (10) so tat gaseousrefrigerant flows into the recovery receptacle (40), wherein the inflowpipe (42) has an exit end which opens downwardly or obliquely downwardlyin the recovery receptacle (40) while, on the other hand, the outflowpipe (43) has an entrance end which is situated above the exit end ofthe inflow pipe (42) in the recovery receptacle (40), and comprisingswitching means (50) for switching the circulation of refrigerant in therefrigerant circuit (10) so that the refrigerant is either circulated toflow through the recovery receptacle (40), or circulated to bypass therecovery receptacle (40), wherein the switching means (50) is made upof: opening/closing valves (51, 52) disposed, respectively, in theinflow and outflow pipes (42, 43) of the recovery receptacle (40), andan opening/closing valve (53) disposed between a connection part of theinflow pipe (42) and a connection part of the outflow pipe (43) of therecovery receptacle (40) in a refrigerant pipe on the suction side ofthe compressor (21).
 3. A refrigeration apparatus, comprising (a) arefrigerant circuit (10) for execution of a vapor compressionrefrigeration cycle including a compressor (21), a heat source side heatexchanger (24), and a utilization side heat exchanger (33) which areconnected by a refrigerant pipe and (b) a contaminant recoveryreceptacle (40) which is connected to the suction side of the compressor(21) by an inflow pipe (42) and an outflow pipe (43), for recoveringcontaminants in the recovery receptacle (40) by causing refrigerant tocirculate in the refrigerant circuit (10) so that gaseous refrigerantflows into the recovery receptacle (40), wherein the inflow pipe (42)has an exit end which opens downwardly or obliquely downwardly in therecovery receptacle (40) while, on the other hand, the outflow pipe (43)has an entrance end which is situated above the exit end of the inflowpipe (42) in the recovery receptacle (40), and wherein: an auxiliaryliquid for the recovery of contaminants is pre-stored in the recoveryreceptacle (40), and the exit end of the inflow pipe (42) of therecovery receptacle (40) is situated at a predetermined distance apartfrom the storage surface of the contaminant-recovery auxiliary liquid.4. A refrigeration apparatus, comprising (a) a refrigerant circuit (10)for execution of a vapor compression refrigeration cycle including acompressor (21), a heat source side heat exchanger (24), and autilization side heat exchanger (33) which are connected by arefrigerant pipe and (b) a contaminant recovery receptacle (40) which isconnected to the suction side of the compressor (21) by an inflow pipe(42) and an outflow pipe (43), for recovering contaminants in therecovery receptacle (40) by causing refrigerant to circulate in therefrigerant circuit (10) so that gaseous refrigerant flows into therecovery receptacle (40), wherein the inflow pipe (42) has an exit endwhich opens downwardly or obliquely downwardly in the recoveryreceptacle (40) while, on the other hand, the outflow pipe (43) has anentrance end which is situated above the exit end of the inflow pipe(42) in the recovery receptacle (40), and comprising: preliminaryoperation means (60) for causing refrigerant to circulate in therefrigerant circuit (10) for a predetermined length of time so that atwo-phase refrigerant mixture of liquid refrigerant and gas refrigerantflows into the recovery receptacle (40), and recovery operation means(70) for causing refrigerant to circulate in the refrigerant circuit(10) so that upon completion of the operation of the preliminaryoperation means (60), gaseous refrigerant flows into the recoveryreceptacle (40).
 5. The refrigeration apparatus of claim 4 wherein thepreliminary operation means (60) increases the degree of opening of anexpansion valve (32) disposed between the heat source side heatexchanger (24) and the utilization side heat exchanger (33).
 6. Therefrigeration apparatus of claim 4 wherein the preliminary operationmeans (60) stops a utilization side fan of the utilization side heatexchanger (33).
 7. The refrigeration apparatus of claim 4 wherein thepreliminary operation means (60) lowers the frequency of the compressor(21) to below a predetermined value.